Method of improving the hydrophilicity of polyurethane cellular product and the resulting product



United States Patent 3 249 465 METHOD OF IMPROVlNG THE HYDROPHILICITY OF POLYURETHANE CELLULAR PRODUCT AND THE RESULTING PRODUCT Patented May 3, 1966 More specifically, the method of this invention comprises soaking the polyurethane sponge material with a dispersion in a liquid carrier containing about 0.1% or higher, but preferably from about 13%, by weight of an essentially water insoluble but water dispersible hydron s n o 5 Ming ggg i gg g fgggg g gggg gfg slmomz philic agent at a temperature of about 20-t35 C., and No Drawing. Filed Aug. 18, 1961, Ser. No. 132,318 Preferably about 5565 C., for a time sufficier t to thor- 7 Claims. (CL 117 93 oughly wet the polyurethane sponge and to retain at least about 1%, but preferably about 520%, by weight of the This invention relates to the method of improving the 10 hydrophilic agent based on the weight of the sponge on hydrophilic properties of polyurethane sponge materials a dry basis. Where substantially no swelling agent is and to the resulting product. present the temperature should preferably be about 45-85 This application is a continuation-in-part of my co- C. In ordinary commercial practice the time can vary pending application Serial No. 752,437, filed August 1, from about 1 second to about 24 hours. At the end of 1958, now abandoned. this time the excess liquid is removed from the sponge Organic foam sponges with interconnecting pores are material as by squeezing. useful as cleaning articles in Washing and scrubbing sur- The resulting treated polyurethane sponge is found to faces. The ideal sponge should not only be capable of be relatively hydrophilic and capable of being more easiabsorbing large amounts of water and to hold the water 1y Wet with water than was the untreated sponge. The for use during the cleaning operation but should also be method of this invention can be used either on polyester easily wet with ater, The different t e f sponges iirethanes or polyether nrethanes and both types will be available for cleaning uses have been somewhat limited. Converted from a hydrophobic condition to a relatively With the product and process of this invention it is now hydrophilic cohditioh- The Preparations of typical P ypossible to produce excellent hydrophilic polyurethane llrethanes are disclosed in numerous US. and foreign sponges (which are normally hydrophobic) that are use- Patents and publicationsy are disclosed in y ful as cleaning articles. pending US. patent application Serial No. 74,463, filed In general, the method of this invention comprises soak- December 1960, now abandoned, and p a y t ing the polyurethane sponge material in an aqueous dis: P g 10 to 21 thereof- The hydrophilic agents that are persion of a hydropholic agent that i e ti ll water preferred in this invention are those that are essentially insoluble but water dispersible. The concentration in the Water insoluble but self-dispersible. Highly water soluaqueous liquid of the agent should be less than that which his agents Such as those of infinite Solubility are not used would damage th ong te ial, Thi a ou t ill because they lose their effectiveness on long rinsing of the vary with the diflerent agents and with the diiferent polytreated p g Thus, the essentially w r insoluble urethanes but is easily determined as an excess concentraagents y be slightly Water Soluble but water dispersible tion ha a solvent and weakening a tion on the u th and still be usable. Oil soluble and substantially cornmaterial. plete-l-y water insoluble hydrophilic agents are dispersed The liquid in which the hydrophilic agent is dispersed in the water by means of a dispersing agent. may be water or may be an aqueous solution or dispersion It has :been observed during the soaking of the sponge of a swelling agent for the polyurethane with these swellin a bath containing the hydrophilic agent that the sponge ihg agents being Well known the art and including actually absorbs the hydrophilic agent from the 'bath, Phatlc 316011015; ketohes, ethefs, halogeha-ted hydfocaf' thus reducing the concentration of the agent in the bath bons and the like. In general, the treating bath should as contact time increases. The bath can be made either not contam of Such ameunt of the Swelhng with water or with water having an organic solvent for that the ig l weakened the agent dispersed therein. Typical solvents are low e temperature 0 e l bath m be above molecular Weight ketones, low molecular Weight aliphatic room temperature where no swelling agent is present but alcohols low molecular Wei ht h th d th may be as low as room temperature where a swelling i b1 b i 1 am e ers an e agent is present. A preferred temperature of the bath is 1 a 8mm 6 at as een found to be f about 20-85 C. with the temperature being preferably up 40-95% Water, 5 60% lmethallol Y in the bottom portion of range (for example about T1118 illustrates those instances where the dispersing agent 20450 C.) when a swelling agent or Solvent for the (e.g. methanol) for the essentially water insoluble hyurethane is present and in the remainder of th range drophilic agent also acts as a swelling agent for the sponge when the bath is substantially Water. The urethane is materialmaintained in contact with the bath until the material has AmOhg the hydrophilic agents that have been found been completely wetted and retains at least about 1% of especially suitable r h method f h n i n r the hydrophilic agent by weight on a dry basis. the following:

N0. Agent Chemical Composition 1 Nlnol HAN Coconut diethanol amide. 2 Makonfi Reactionproductofonemolenonyl phenol andsmoles of ethylene oxide. 3 ispersant NI-O Reaction product of one mole alkyl phenols containing G g-CH (average Cis)-ii1 the alkyl groups and 4-5 moles ethylene oxide. 4 Renex 36 Reaction product of one mole tridecyl-a1cohol-and6 moles of ethylene oxide. 5 Triton X-155. Reaction product of one mole octyl phenol and 57 moles of ethylene oxide.

N Agent Chemical Composition 6 Alkaterge A. CH3ON /C-C17 n CIITO CIIiOI-I 7 Alkatergo E- GI-I CH CN\\ I C-CnHsa CHzOH 8 Alkatcrge O CH3ON OH O 9 Alkaterge T (7111011 CHaOI-ION CHz-O Disporsant NI-E Reaction product of one mole alkyl phenols containing Ola-Cw (average 015) in the alkyl groups and 3-4 moles ethylene oxide. 11.. Triton X-1l4 Reaction product of one mole t-octyl phenol and 7 to 8 moles of ethylene oxide.

5 (CI'I3)3C CHg-(|]C o ornonnmon CH3 I where m=78 12.-.- Triton X- Reaction product of one mole t-octyl phenol and 5 moles of ethylene oxide. l3 E1 Reaction product of one mole tallow alcohol and 2 moles glthyglele oxide, average alkyl carbon chain length of 16 0 1H. 14 E Reaction product of one mole tallow alcohol and 4 moles ghszlere oxide, average alkyl carbon chain length 0t 16 0 8. 15 Amidox o2 Ethoxylatied alkylol-amide of essentially the formula:

CnHg5C ON(CgH4O (3111 01 1);

16. Triton N57 Nonyl phenoxy polyethoxy ethanol of essentially the formula:

otnnw OHzCHg 5OH The usable hydrophilic agents of which the above list is exemplary are either oil soluble (soluble in organic solvents) or essentially Water insoluble but water dispersible either with a dispersing agent such as methanol or even without a dispersing agent in some instances. This insures their retention in the foam or sponge (terms used herein interchangeably) without premature loss of hydrophilic characteristics. Water dispersions of those selfdispersing hydrophilic agents are easily made by merely adding them to the water. However, if the material is oil soluble such as agents.68 of the above list, it will not disperse in water without the addition of a dispersing agent. In order to disperse this type of material in water an additional dispersing agent such as Tergitol NPX (a reaction product of one mole nonyl phenol and 10 moles of ethylene oxide) should be used or if desired a mixture of alcohol and water can be used as a dispersant.

As pointed out above, the sponges that are treated by the method of this invention may be any of the polyester or polyether urethanes. Whether in the form of a sponge or a sheet the urethane are rendered hydrophilic by the method of this invention. Typical methods of making polyurethanes are disclosed in my above-mentioned copending application Serial No. 74,463, and these are exemplary only.

A polyol polyurethane sponge prepared by Example 1 of my US. application Serial No. 74,463 was prepared as follows:

A prepolymer resin was prepared by the following procedure: 444.8 lbs. of Pluronic. L-61, hydroxyl number 50.5, was premixed with 63.5 lbs. of PPG-400, hydroxyl number 288.8, representing a hydroxyl equivalent ratio of 0.4448 to 0.3635. This polyol mixture should have a hydroxyl number of -81 and the acid number was adjusted to .03 and water content to 0.39%. To this mixture 235 lbs. of toluene diisocyanate, .002 to 003% total acidity, were added while mixing. The NCO/ OH ratio was about 3.44. After 30 minutes the heat of reaction cansed the temperature to rise to about 130 F. With additional heating requiring 2 hours, the mixture reached a temperature of 212 F. The reaction was allowed to proceed at 212 F. until the viscosity was about 3900-4200 centistokes. The resulting prepolymer was cooled to -125 F. It contained about 9.35% free NCO. The total process took about 8 /2 to 9 /2 hours.

For each 100 parts by weight ofthe above prepolymer, previously adjusted to 9.8% free NCO, the following were added:- 0.2 part of silicone fluid DC-200 (polydimethylsiloxane) at 25 C. 50 centistokes viscosity, 17 parts Titanox RCHT-X and .167 part Benzedine Yellow No. 12220 dye.

A catalyst solution was made as follows: 15 parts water 1.5 parts triethyl amine and 5 parts diethylethanol amine.

The sponge material was prepared by foaming as follows:

Precision metering pumps were used to pump out the prepolymer resin/ catalyst solution in the ratio of 32-25 :1

to a mixing head having a capacity of 100 ml. Six triple blade turbine mixers were employed using a mixing speed of 3400 r.p.m. To facilitate the resin pumping, the resin was heated to 120 F. The rate of pumping was about 5 pounds per minute. The mixed material was delivered to a box-shaped mold through a opening where foaming took place immediately. After approximately minutes, the foams rise discontinued. After 30 minutes, it was removed from the mold and crushed by running between closely spaced squeeze rollers to break any closed cell walls, then postcured in a hot air oven at 185-190 F. for 16 hours. All said parts are by weight.

The Pluronic L61 has the formula It has a molecular weight of the polyoxypropylene base of about 1501-4800 and an oxyethylene content of about 10%. The PPG-40O is polypropyleneglycol with a molecular weight of about 400. The Titanox RCHT-X consists of calcium sulfate particles coated with titanium dioxide.

A section 1" x 3%" x 5 /4" was cut from this sponge. Then a water dispersion was made up with 1.5% of hydrophilic agent No. 3 in the above list, all percentages being by weight. The section of sponge was saturated by this bath maintained at a temperature between 5560 C. for about 10 minutes. Then the sponge was removed from the bath and wrung out. At the end of this time the sponge contained about 14.5% hydrophilic agent on the dry basis. Before this treatment the sponge had been found to float on water without wetting. As a result of this treatment the sponge became wet with water at a rate of less than 2 seconds per centimeter of thickness even after being rinsed with 2000 gallons of room temperature water at the rate of 500 gallons per hour.

Similar examples were performed using the polyurethanes prepared according to my above-mentioned application No. 74,463 and various of the hydrophilic agents in the above list. In every instance the polyurethane sponge material which before treatment had been hydrophobic was hydrophilic after the treatment. These examples were all performed within the conditions defined earlier in this application.

In other examples polyurethane foams were prepared according to Examples 2, 3, 4 and 5 of the above-mentioned application 74,463. Also, 1.5 aqueous dispersions of hydrophilic agents 2, 4, 5 and 11 of the above list were prepared. Each of the polyurethanes was soaked in one of these dispersions at temperatures of about 40-60" C. for 10 minutes time. At the end of this time the excess dispersion was removed and the polyurethane was found to be highly hydrophilic.

Similar tests were run using hydrophilic agents 9, l3 and 14 of the above list with the above-designated polyurethanes. In each of these instances the hydrophilic agents were dissolved in methanol and diluted with water to give a dispersion concentration of 1.5 of the agent in a 5% methanol-95% water mixture. The sections of urethane sponge were soaked in these dispersions for about 10 minutes at 40-60 C. at the end of which time the excess dispersion was removed. The sponges likewise were found to be hydrophilic. In each of these tests sections of the above-described dimensions were used.

In all of these tests the polyurethane foam material remains hydrophilic even after being continuously rinsed with room temperature water for 24 hours.

The essentially water insoluble but water dispersible hydrophilic agents of this invention appear to function by a physical action and not a chemical action. Thus, they appear to operate regardless of their chemical structure so long as they are dispersible in water but not water soluble so that the effect will not be lost too rapidly on contact with water. Furthermore, the action of the usable hydrophilic agents does not appear to depend upon the ionic character of the agent. The important determination of whether a hydrophilic agent will work or not is that it be water insoluble in that the agent is not completely dissolved even in the minimum amount recited above which is at least about 0.1% by weight in the aqueous dispersion.

The swelling agents mentioned herein have a solvent action on the sponges and thus the terms swelling agents and solvents are used interchangeably herein. Among the dispersing agent for the non self-dispersible surface active agents are the solvents mentioned above. Thus, these dispersing agents may be water soluble, low molecular weight ketones, water soluble, low molecular weight alcohols, water soluble low molecular weight ethers and the like which also act as the swelling agents or solvents. The dispersing agents also include, however, water soluble surface active agents of which the above-described Tergitol NPX is an example. The dis persing of essentially water insoluble but water dispersible hydrophylic agents is well understood in the hydrophilic agent art, as this is frequently done in order that they can be used in an aqueous medium.

Having described my invention as related to the embodiments set out herein, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

I claim:

1. The method of improving the hydrophilicity of a polyurethane foam material, comprising: preparing a dispersion of an essentially water insoluble but water dispersible hydrophilic agent in a bath of the class consisting of water and aqueous solutions of a dispersing agent for said hydrophilic agent, said bath containing at least about .1% by weight of said bath of said hydrophilic agent; saturating said material with said bath maintained at a temperature within the range of about 20-85" C. for a time sufiicient for said foam material to absorb at least about 1% of said hydrophilic agent by weight of the anhydrous foam material, said temperatures being the bottom of said range when said bath is said solution and in the remainder of the range when said brat-h is substantially Water; and removing said material.

2. The method of improving the hydrophilicity of a polyurethane foam material, comprising: preparing a dispersion of an essentially water insoluble but water dispersible hydrophilic agent in a bath of the class consisting of water and aqueous solutions of a dispersing agent for said hydrophilic agent, said bath containing at least about .1% by weight of said bath of said hydrophilic agent; saturating said material with said bath maintained at a temperature within the range of about 2085 C. for a time sufficient to absorb about 520% of said bydrophilic agent by weight of the anhydrous foam material, said temperature being in the bot-tom of said range when said bath is said solution and in the remainder of the range when said bath is substantially water; and removing said material.

3. The method of improving the hydrophilicity of a polyurethane foam material, comprising: preparing a dispersion of an essentially water insoluble but water dispersible hydrophilic agent in a bath of the class consisting of water and aqueous solutions of a dispersing agent for said hydrophilic agent, said bath containing at least about 12% by weight of said bath of said hydrophilic agent; saturating said material with said bath maintained at a temperature within the range of about 20-85 C. for a time sufficient to absorb about 5-20% of said hydrophilic agent by weight of the anhydrous foam material, said temperature being in the bottom of said range when said bath is said solution and in the remainder of the range when said bath is substantially water; and removing said material.

4. The method of improving the hydrophilicity of a polyurethane foam material, comprising: preparing a dispersionin an aqueous bath of at least about .1% by weight of said bath of. the hydrophilic agent reaction product of one mole of an alkyl phenol containing 12-16 carbon atoms in the alkyl groups and 4-5 moles ethylene oxide; saturating said material with said bath maintained at a temperature within the range of about 20-85" C. for a time sufficient to absorb at least about 1% of said hydrophilic agent by weight of the anhydrous foam material; and removing said material.

5. A hydrophilic product comprising: a polyurethane foam material having internal pores; and at least 1% on an anhydrous weight basis of an essentially water insoluble but water dispersible hydrophilic agent absorbed therein.

6. The product of claim 5 wherein said amount is about 5-20%.

8 7. The product of claim 5 wherein said surface active agent is the reaction product of one mole of an alkyl phenol containing 12-16 carbon atoms in the alkyl groups and 4-5 moles ethylene oxide.

References Cited by the Examiner WILLIAM D. MARTIN, Primary Examiner.

RICHARD D. NEVIUS, Examiner. 

1. THE METHOD OF IMPROVING THE HYDROPHILICITY OF A POLYURETHANE FOAM MATERIAL, COMPRISING: PREPARING A DISPERSION OF AN ESSENTIALLY WATER INSOLUBLE BUT WATER DISPERSIBLE HYDROPHILIC AGENT IN A BATH OF THE CLASS CONSISTING OF WATER AND AQUEOUS SOLUTIONS OF A DISPERSING AGENT FOR SAID HYDROPHILIC AGENT, SAID BATH CONTAINING AT LEAST ABOUT .1% BY WEIGHT OF SAID BATH OF SAID HYDROPHILIC AGENT; SATURATING SAID MATERIAL WITH SAID BATH MAINTAINED AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 20-85*C. FOR A TIME SUFFICIENT FOR SAID FOAM MATERIAL TO ABSORB AT LEAST ABOUT 1% OF SAID HYDROPHILIC AGENT BY WEIGHT OF THE ANHYDROUS FOAM MATERIAL, SAID TEMPERATURES BEING THE BOTTOM OF SAID RANGE WHEN SAID BATH IS SAID SOLUTION AND IN THE REMAINDER OF THE RANGE WHEN SAID BATH IS SUBSTANTIALLY WATER; AND REMOVING SAID MATERIAL. 